Magnetic Signatures and Magnetization Mechanisms for Grinding Burns Detection and Evaluation

Area of Science:

• Materials Science
• Non-Destructive Testing
• Magnetism

Background:

• Grinding burns, caused by excessive heat during grinding, degrade steel component properties.
• Current detection methods like nital etching are effective but environmentally harmful.
• Magnetization mechanisms offer a promising, eco-friendly alternative for detecting grinding burns.

Purpose of the Study:

• To investigate magnetic responses for detecting grinding burns in steel.
• To correlate magnetic properties with mechanical characteristics and burn severity.
• To identify reliable magnetic indicators for grinding burn assessment.

Main Methods:

• Metallurgical treatment of steel specimens (18NiCr5-4, X38Cr-Mo16-Tr) to induce varying grinding burn levels.
• Mechanical characterization including hardness and surface stress measurements.
• Magnetic measurements: magnetic incremental permeability, magnetic Barkhausen noise, and magnetic needle probe.

Main Results:

• Mechanisms related to domain wall motion demonstrated high reliability.
• Coercivity, derived from Barkhausen noise and incremental permeability, showed the strongest correlation with grinding burn levels.
• Correlations between grinding burns, surface stress, and hardness were weak, suggesting microstructural influences.

Conclusions:

• Magnetic methods, particularly coercivity measurements, are reliable for detecting grinding burns in steel.
• Magnetization mechanisms, especially domain wall motion, are key indicators.
• Microstructural properties likely play a more significant role in magnetic responses than bulk mechanical properties.